6502.org

Posted: **Fri Sep 28, 2012 7:55 pm**

BigEd wrote:

Another small SBC design is Halldor's - the site has been intermittently offline but is up at present.

Early on in the start of my POC project I looked at Hallidor's design for ideas. It's a good basic design that anyone with a reasonable amount of diligence should have no trouble bringing to life.

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It would be easy and desirable to substitute a clock can, unless explicitly teaching the workings of a crystal oscillator.

Something I would highly recommend. Fewer parts and a better quality clock signal, for one. Also, if the oscillator can is socketed, the Ø2 frequency can be readily changed during the course of experimentation without having to be concerned with how well the clock circuitry will work.

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He's using DIL headers and ribbon cable for expansion, which will be OK for very short distances. It wouldn't be difficult to swap in alternate grounds and the necessary extra headers, if that was a concern.

Right. The alternating ground principle (a feature I first saw in the SASI bus of the early 1980s) can make ordinary ribbon cable perform at pretty high frequencies. Of course, distance is going to be limited by capacitive loading unless bus transceivers are employed, but then the circuit would start to exceed the complexity level that should exist in a basic design.

One very minor quibble I have with Halldor's site (and this is mostly due to personal issues) is his use of color in his schematic. We older blokes generally don't have the vision of a twenty-year-old and in my case, I have partial blue-green color blindness that renders some details on his schematic invisible to me. Usually I counteract that in an image in which I am interested by copying it into an image viewer and disabling color. Or I print it using monochrome.

For personal use, color obviously can be a benefit, especially if there is quite a bit of complexity. However, in something that is to be publicly displayed, some consideration of viewability is beneficial. In my own work (especially mechanical drafting, where color helps to discern layers and hidden views) I stick to high contrast colors that I can readily discern, knowing that if anyone else has to view the drawing they will probably be able to see the detail with some clarity.

Posted: **Fri Sep 28, 2012 8:12 pm**

GARTHWILSON wrote:

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The other trend is that hardware is dead:

http://venturebeat.com/2012/09/15/hardware-is-dead/

That article is a strictly consumer point of view, with no thought of industrial or workbench or hobby applications. The A-Pad he got for $45 will be in the land fill in two years, maybe six months. If it breaks down, there will be no support whatsoever. If you want to do your own thing with it, there will be no documentation, let alone complete documentation, of what's inside. Even if there were, it would take much longer to learn it than the product will be available. For someone who wants to learn computers (after all, this is the "SBC kit for evaluation" topic), they have no hope of getting down-to-the-metal control of the computer, including microsecond timing of anything, and it has absolutely no general-purpose I/O bits.

The A-Pad actually does everything the Amazon Kindle Fire does with the exception that you have to use a different store like Google Play and it runs Android Icecream Sandwich which means the apps are much better than the Kindle.

Our laptop broke and I bought a refurbished Amazon Kindle Fire on sale. It lets me read everything on the internet and it lets me log into websites. I took it on vacation and it was very handy except the motel internet kept going out. It is very light and I have a case for it so unless it wears out, I'm keeping it and my hardware usually lasts 5-6 to 10 years or more. I don't see any reason to get rid of it. My motivation to getting a Kindle was that my bookshelves were full and I didn't have any more room in my house. You also get some free stuff online because there are e-books and I also learned how to send myself word processing documents that I can read on the Kindle. I can get an internet radio station and I can also buy and play music on it and my files are backed up on free internet storage.

For $35, an A-Pad is a better deal than the Kindle Fire with the exception of the store it is on. For that price, I would get backups because I and other people occasionally break things like our mobile phones. For that price, you should just go out and buy a new one rather than expecting support because it is cheaper to just buy the tablet new again.

I repaired my Tom Tom GPS because I found out online how to replace the battery and I bought a new battery off of ebay and a youtube video showed me what to do because it is only four screws and some adhesive take that you have to remove. I am a person that keeps my computers and hardware forever.

Posted: **Fri Sep 28, 2012 8:13 pm**

whartung wrote:

The SBC project would be interesting, but it's becoming less and less necessary for those wanting to dabble in this field. Those who want to make it a profession will pick this and much much more up during their engineering studies.

I'm not so sure about that. Reading about computer hardware and actually designing and building computer hardware are hardly in the same league. Saying otherwise is akin to asserting that "making music is easy: just play the right notes at the right time." To use yet another analogy, one can study all the cookbooks in print, yet still be unable to prepare a tasty and nourishing meal because s/he lacks the "chops" required to do so.

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This is why it is so important to understand when undertaking a project why you are doing it. If you just want to make blinky lights, a 6502 SBC is the long way around to get there today. If you want to understand 6502 architecture and programming, there's a zillion simulators out there you can use. If you want to perfect your wire wrap technique, perhaps an SBC project is the thing for you.

And if you want to be able to point to something and say "I created this." scratch-building an SBC is the only real route. Everything else is mere assembly. You can't rightfully say you built your own home if you didn't do the architectural work, frame it, lay brick, etc.

Posted: **Fri Sep 28, 2012 8:45 pm**

ChuckT wrote:

GARTHWILSON wrote:

Quote:

The other trend is that hardware is dead:

http://venturebeat.com/2012/09/15/hardware-is-dead/

That article is a strictly consumer point of view...

The A-Pad actually does everything the Amazon Kindle Fire does...

Chuck, I think you may have missed Garth's point. It isn't an question as to whether a Kindle is better than a Nook (beats me as to which is better) or what to do when your laptop goes on the fritz (they all eventually do). These items are appliances akin to a toaster or a microwave oven. You use them but they don't teach you anything of value in the process.

The "gadget mentality" that is promoted by the I-Pads, Kindles and Tom-Toms of the world marginalizes learning and has increasingly produced a dumbed-down population that is unable to function when the gadget de jour conks out. My nearly 18-year-old grandson knows all about "smart" phones and GPS usage (which doesn't keep him from being led down the proverbial dirt road on occasion) but doesn't know diddly about balancing a checkbook, computing the area bounded by a circle (What's this pi thingie anyhow?) or why socialized healthcare might or might not be a good thing.

Posted: **Fri Sep 28, 2012 8:58 pm**

I'm also thinking about useful applications (ie, not just for fun and learning) on the workbench that one can do with a 6502 but not with the pre-packaged computers that have so many layers between the user and the heart of the computer. It's not that the iPads and so on don't have their place. They definitely do; but it's a different thing, a different market, and they do not replace the small computer where you have total control over what goes on in every microsecond and every machine-language instruction and every bit of I/O.

One of my values to my employer is that I can easily come up with ways to use the workbench computer to substitute for different pieces of expensive (many thousands of dollars) lab equipment that this small company cannot afford to buy for the isolated project here or there, or even take the time to find and rent for a few months at one-third the purchase price.

And as for development time, those who know the insides of their machine can indeed get the proverbial "blinky lights" in a few minutes of programming, with no underlying layers of software.

Posted: **Fri Sep 28, 2012 9:10 pm**

I think I've mentioned him before, but https://github.com/dwelch67/raspberrypi covers various bare-metal knowledge for the Pi. It's good that it can be used both at the abstract and easy level of python and scratch, and also at the machine level.

However, I think we all agree that to learn systems design you need to have a system laid out in front of you, and an SBC of some form is what's needed. I don't believe you have to design it yourself, but building it or at least wiring it is probably slightly better than stuffing components into a board. But even that - which is what I did 35 years ago - is educational, when the parts are CPU, peripherals, memory and control logic.

Posted: **Fri Sep 28, 2012 10:59 pm**

whartung wrote:

Arduino et al is better for those trying to install it on something else. It's not self hosting, you need to build, download, execute, rinse, repeat, but the community around it is nice and high level, artists and "makers" rather than in the trench engineers. Super accessible, instant robots, etc. Arduino helps make the entire field less intimidating.

Couldn't agree more!

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The SBC project would be interesting, but it's becoming less and less necessary for those wanting to dabble in this field. Those who want to make it a profession will pick this and much much more up during their engineering studies.

I don't want to make it a profession. I just want to learn.

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If you just want to make blinky lights, a 6502 SBC is the long way around to get there today.

Again, I want to learn and understand how computers work and I'm not alone.

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If you want to understand 6502 architecture and programming, there's a zillion simulators out there you can use. If you want to perfect your wire wrap technique, perhaps an SBC project is the thing for you.

Wrong. The discussion is about a kit for the genreral public, not me wanting to learn WW. Emulations? Are you serious? If emulations were enough, we wouldn't be in this forum.

Posted: **Fri Sep 28, 2012 11:00 pm**

BigDumbDinosaur wrote:

I'm not so sure about that. Reading about computer hardware and actually designing and building computer hardware are hardly in the same league. Saying otherwise is akin to asserting that "making music is easy: just play the right notes at the right time." To use yet another analogy, one can study all the cookbooks in print, yet still be unable to prepare a tasty and nourishing meal because s/he lacks the "chops" required to do so.

When I went to school back in the days when we filled out our slates by candle light in the snow and were grateful for it, the engineering students actually had to build things. In our CS Logic class where we talked gates, flips flops and Karnaugh maps (ha! spelled that right the first time...), we were tasked with building a 4 Bit ALU. That was the Computer Science curriculum, not the EE or CE. They did a lot more with hard parts over there than we did.

I don't know what they do today. Maybe it's all VERILOG in simulators, but I assume they still do some wire to pin work. But to be fair, many of the senior term student projects from the Information Tech program (I think it's called) over here at UC Irvine, when they used hardware at all, it was certainly at the assembled modules level of "camera or sensors plugged in to laptop" level of hardware integration. Understandable since this is mostly a software based curriculum.

BigDumbDinosaur wrote:

And if you want to be able to point to something and say "I created this." scratch-building an SBC is the only real route. Everything else is mere assembly. You can't rightfully say you built your own home if you didn't do the architectural work, frame it, lay brick, etc.

That's right, but that wasn't my goal in getting my home either. However despite not designing, framing, bricking, or wiring it, I get to live comfortably in it, invite folks over to it, paint the walls colors I like, nail pictures in to said walls, and keep my possessions and pets mostly safe from harm.

The point simply being that computer circuit design is no longer a requirement for the vast majority of use cases that people may want to use a computer for, including modern hardware integration.

I mean, look at this thing: http://www.brielcomputers.com/wordpress/?cat=25

A "smart terminal" made from a PC keyboard and a VGA monitor. Components: 3 Chips, a (very sophisticated) micro controller, an EPROM and a RS-232 chip. This was not a hardware problem, this was a software problem. I can't say, but for all I know most of the "hardware design" of this came off of the application notes. (And I'm not trying to disparage the designers skills here.)

Could I have done something like this via paint by number integration of app notes (modulo the software complexity)? Maybe. Would I have had the confidence to try it? Certainly not. But others do, other are doing so today with little training outside of perhaps youtube videos and blog posts.

So, yea, if you want the satisfaction of building a computer from the chip level, a 6502 project would be ideal. It is interesting to me. If your goal is something else, some other integration or design project, it's not necessary, not anymore.

Posted: **Fri Sep 28, 2012 11:03 pm**

alkopop79 wrote:

Emulations? Are you serious? If emulations were enough, we wouldn't be in this forum.

Heh -- to be fair, that IS why I'm here

. I wanted to do some low level programming and such, and decided to do so by creating my own emulator and assembler.

Posted: **Fri Sep 28, 2012 11:13 pm**

whartung wrote:

alkopop79 wrote:

Emulations? Are you serious? If emulations were enough, we wouldn't be in this forum.

Heh -- to be fair, that IS why I'm here

. I wanted to do some low level programming and such, and decided to do so by creating my own emulator and assembler.

Making an emulator sounds more exciting than using one. How you doing with that project? Any details?

Posted: **Fri Sep 28, 2012 11:21 pm**

BigDumbDinosaur wrote:

The "gadget mentality" that is promoted by the I-Pads, Kindles and Tom-Toms of the world marginalizes learning and has increasingly produced a dumbed-down population that is unable to function when the gadget de jour conks out. My nearly 18-year-old grandson knows all about "smart" phones and GPS usage (which doesn't keep him from being led down the proverbial dirt road on occasion) but doesn't know diddly about balancing a checkbook, computing the area bounded by a circle (What's this pi thingie anyhow?) or why socialized healthcare might or might not be a good thing.

I had to go to work after we were hit by a high weather cell of water. We had flooding and my relative's power was out for a week. My doctor tried to get to work, spent an hour and a half in the car until he turned around and went home. My commute is 12 miles to work and I was detoured three times before I could get to work. If it wasn't for GPS, I wouldn't have gotten to work and it has saved me countless hours and I've learned how to get places by following the GPS so learning doesn't take as long.

Our company has an index card system for inventory as backup and we use the computer for inventory. When the computer is down which has happened when the server died once in the last 15 years, we used index cards. Can I tell you that without the computer, very little got done? Before we had the computer, you had to have a file room and hire someone to pull the file and put it away in a filing cabinet. Without the computer, someone has to spend lots of time looking up products in a dozen different product catalogs that are thicker than several phone books stacked together. We have computers that replace people so they don't have to do that.

The gadget mentality has made us more competitive and as a result we have to take in more information and not less.

Posted: **Sat Sep 29, 2012 5:11 am**

It's clear to me, and I wish it were clear to everyone, that different people have different goals and interests. They often overlap, and on this forum they overlap around the 6502. But we are not the same as each other, and there's not much benefit promoting one sub-collection in preference to another: some of us are here for assembly-language programming, some for emulator construction, some for homebuilt systems ranging from homebuilt CPUs to commercial kits. Of course that's not an exhaustive list!

Similarly, for education there are different end-goals and different disciplines. Introducing the under-12s to programming is a different problem to teaching Computer Systems Engineering to undergraduates.

By all means let's discuss the full breadth and range of all those things, but let's not get distracted by unanswerable questions about which is best or which is not worthwhile.

Cheers
Ed

Posted: **Sat Sep 29, 2012 5:37 pm**

ChuckT wrote:

The gadget mentality has made us more competitive and as a result we have to take in more information and not less.

I completely disagree (mostly, gadget mentality has made the average user less capable of independent thought and action), but that's not germane in this particular topic.

This topic is supposed to be about a 6502 DYI SBC education kit that gives the experimenter the opportunity for "bare metal" learning of a type that cannot be be provided in a prefabricated gadget. Unfortunately, the topic seems to have seriously digressed. All of you who have been advocating Arduino this and Raspberry Pi that are completely missing the point. Neither device facilitates, let alone encourages, experimentation at the basic "bits-and-bytes" hardware level. The Pi, in particular, is little more than a truncated PC, with PC-like characteristics (USB, etc.) but not equipped with an x86 MPU. Yes, you can run Linux on it, but that hardly qualifies it as an experimenter's tool (I can run Linux on an el cheapo PC slapped together with commodity parts). The would-be experimenter is limited to what has been provided in the hardware and would experience difficulty in adapting the device to a one-off application where special/non-standard hardware interfacing is required. Let's see you, for example, connect a SCSI disk to the Pi and achieve anything resembling satisfactory performance.

Something that I have stated several times, and will repeat (no doubt to the dismay of at least one member), is that I joined 6502.org because of its relatively narrow focus on the 6502 MPU family and the ways in which it can be adapted to different uses. Discussion about Pis, Arduinos, MC68000 systems, GPS devices, I-Pads, etc., is content dilution and while not always detrimental to this forum's primary focus, can be distracting. Yes, I can (and do) ignore some of these posts, just as someone at a forum devoted to Corvettes can choose to skip over posts about Jaguar or Maserati automobiles. However, I can't ignore posts of these kinds in topics in which I am interested, and the seemingly-endless Pi posts, in particular, which all-too-frequently appear in topics discussing 6502-specific matters, have become an annoyance.

I'll finish my diatribe with this: if anyone here thinks the Arduino, Raspberry Pi, et al route is so great and that the concept of scratch-building a computer around a 65C02/65C816, appropriate glue logic and I/O is passé/obsolete/pointless, I must ask of you: Why are you here?

Posted: **Sat Sep 29, 2012 5:46 pm**

No one says that. They're just interesting models of education. Anyone who breaks down the barriers between people and technology deserves respect. Both the Arduino and Rasp Pi people did what they did for this reason. Anyway, let's get back to the topic...

Posted: **Sat Sep 29, 2012 5:56 pm**

alkopop79 wrote:

No one says that.

Sure they did. Please re-read some of the comments.

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Both the Arduino and Rasp Pi people did what they did for this reason.

Not exactly. To quote you in your opening post:

- the kit could fill the vacuum left by the Arduino microcontroller and the Raspberry Pi SBC. These devices have attracted a large crowd yet they do not explain how computers, processors and other digital hardware work

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Anyway, let's get back to the topic...

...which is about a 6502 DYI hardware kit, not something powered by an ARM.

I guess my point (and Garth's point) just isn't getting through.

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